Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint, openWorldHint and destructiveHint=false, so the safety profile is covered. The description adds genuinely useful access context that annotations cannot carry: API-key requirement, USD keyless vs. subscription_required for other currencies, and a subscribe link. It says nothing about result volume, pagination defaults, or what a listing response looks like.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Front-loaded with the core purpose, then a dense but necessary enumeration of the four families, then access constraints last. The single vaguer sentence ('Omit the selector to list what a family holds') is the only real ambiguity in an otherwise tight paragraph.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

With 11 parameters, an output schema, and full annotations, the description covers the family taxonomy, listing behavior, currency scoping, and auth tiers – enough for an agent to call it correctly. Minor gaps remain around pagination defaults and the family-specific filters object, though the output schema and param descriptions absorb most of that.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so the baseline is 3, but the description earns extra credit by explaining what each family enum value actually contains, which the enum labels alone do not convey. It also clarifies currency scoping ('for financial_prices and official_dataset') beyond the schema wording, though it does not touch pagination or date-bound behavior.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb (read/list) and resource (official datasets), then enumerates all four families and the concrete data each contains (yield curves, TIC positions, balance of payments, trading updates). It contrasts itself with 'headline indicators' (the indicator_query sibling) but never names an actual sibling tool, so differentiation is implied rather than explicit.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Gives one useful usage rule – 'Omit the selector to list what a family holds' – which tells the agent to probe before reading. However, 'the selector' is ambiguous (it reads as if family could be omitted, contradicting the required family param), and there is no explicit guidance on when to choose this over indicator_query, rate_curve, or release_calendar.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.